Japanese and U.S. negotiators concluded nearly two weeks of discussions on passenger airline routes and fares here Tuesday and indicated they had not made much progress.

Left unresolved were Japan's bid to open more routes into major American cities and the U.S. effort to lower air fares and bring more charter passenger flights into this country.

"We had hoped to make more progress than we did," said the chief U.S. negotiator, Julius L. Katz, assistant secretary of state for economic and business affairs.

He said that Japan's participants had been unwilling to discuss in detail the questions of charter flights and lowered fares, although they had not ruled out the possibility of talking about those issues at a later date.

On the other hand, Katz acknowledged that the United States was not prepared yet to go into detail on the Japanese plan to expand routes for Japan Air Lines, which wants access to such major American markets as Dallas, Miami, Chicago, Seattle and Houston.

He said the United States wants to discuss such new routes - strongly opposed by American passenger airlines - only in the context of a general expansion of competition and services for both countries.

Spokesmen for the two sides left the impression that few details were covered during the meetings here and that the only decision reached was to meet again in Washington soon. The date tentatively was set for Nov. 28.

Japan has resisted detailed discussion of the request of several U.S. companies to expand charter services to Japan.

It is occasionally suggested here that Japan, which has sought revision of the agreement for five years, will become impatient and terminate it unilaterally.

One Japanese official present at the talks said today his government is not considering termination. "That is an unfounded rumor," he said.

Katz told reporters after the talks concluded that, "despite our differences we believe agreement is possible."